On the tribology of complex 2D/3D composites bearing

Author(s):  
Saeed Reza Zahabi ◽  
Mohammad Sheikhzadeh ◽  
Saleh Akbarzadeh ◽  
Addie Bahi ◽  
Frank Ko

In the present work, a hierarchical braided polymer composite consists of Polytetrafluoroethylene (PTFE) fibers, reinforcement fibers, and epoxy resin was designed as a self-lubricant composite and bearing. Different reinforcements such as glass, carbon, and Kevlar fibers were employed to investigate the effect of reinforcement on the wear characteristics of composites. Besides, the influence of 2D/3D braid fabric was examined on the wear behavior of samples. Also, 90 and 120 N loads were applied to assess the load impact. Results illustrated that compared to glass and Kevlar, carbon could lead to a greater wear weight loss and friction coefficient. However, PTFE tribofilm was observed according to scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDS) analysis. Moreover, with the increase of load, the wear stability of the composites faded significantly. Furthermore, the tribological features became inappropriate with the deployment of the 3D braid structure. Finally, the modeling of tribological parameters was carried out using response surface methodology-based D-optimal design. The adequacy of the models was checked by analysis of variance. Results implied that there is an excellent correlation between the model and the experiments.

2020 ◽  
Vol 34 (7) ◽  
pp. 8848-8856
Author(s):  
Elena V. Fomenko ◽  
Vladimir V. Yumashev ◽  
Sergey V. Kukhtetskiy ◽  
Anatoliy M. Zhizhaev ◽  
Alexander G. Anshits

2007 ◽  
Vol 546-549 ◽  
pp. 1699-1702
Author(s):  
Xi Ying Zhou ◽  
Liang He ◽  
Yan Hui Liu

Al-Cu-Fe quasicrystals powder was used to prepare the thin films on the surface of the A3 steel by the means of DMD-450 vacuum evaporation equipment. The thin films with different characterization were obtained through different parameters. The microstructures of the thin films were analyzed by Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). Additionally, the nano-hardness and the modulus of the films are tested by MTS and Neophot micro-hardness meter. The results showed that the modulus of the films was about 160GPa. Nano hardness of the films was about 7.5 Gpa. The films consisted of CuAl2, AlCu3. The thickness and the micro-hardness of the films are improved. In same way, with the increase of the electric current, the thickness and the hardness of the films are also improved. Along with increase of the time and the electric current, the wear behavior of the films was improved. To some extent, the microstructure of films contained the quasicrystal phase of Al65Cu20Fe15.


Nukleonika ◽  
2017 ◽  
Vol 62 (2) ◽  
pp. 177-181 ◽  
Author(s):  
Agata Stoch ◽  
Jan Maurin ◽  
Paweł Stoch ◽  
Jan Kulawik ◽  
Dorota Szwagierczak

Abstract Multiferroic 0.5BiFeO3-0.5Pb(Fe0.5Ta0.5)O3 solid solution is a material that exhibits ferroelectric and antiferromagnetic orderings in ambient temperature. The solid solution was obtained as a result of a conventional reaction in a solid state. The obtained material is a dense, fine-grained sinter whose surface was observed by scanning electron microscopy (SEM) and stoichiometry was confirmed by energy dispersive X-ray spectroscopic (EDS) analysis. According to the X-ray powder diffraction (XRD) measurements, the main phase is R3c space group with admixture of Pm-3m regular phase. Small contribution of pyrochlore-like phase was also observed. Mössbauer spectroscopy suggested random distribution of Fe3+/Ta5+ cations in the B sites of ABO3 compound. Reduction of the magnetic hyperfine field with an increase in the substitution of Ta5+ in Fe3+ neighbourhood was also observed.


2014 ◽  
Vol 675-677 ◽  
pp. 140-144
Author(s):  
Chun Ying Liu ◽  
Xiao Feng Gong ◽  
Ju Yun Yang

The physico-chemical properties of iron plaques formed on the root surfaces ofCmarex cinerascensunder laboratory conditions were determined using Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectrometry (EDS) analysis. Iron plaques were present as an amorphous coating on root surfaces with an uneven distribution. EDS analysis showed that iron plaques were composed of Fe , Si, Al and lesser amounts of Ca in plaqued root surfaces.


Author(s):  
Sergey Leonov

Abstract. The article is devoted to the possibilities of innovative research methods in forensic medicine-scanning electron microscopy with energy-dispersion analysis. The described methods were used in conducting experimental studies in the case of a gunshot retrograde injury. Aim. The purpose of the work was to study the particles formed during the destruction of a semi-shell shell and an obstacle (triplex car glass) when fired from a hunting Saiga carbine with 5. 45x39 cartridges. Material and methods. Car triplex windshields from BMW and Mercedes-Benz cars were used as a barrier. The shots were fired from a hunting Saiga carbine with a 5.45x39 cartridge. The shots were fired from a distance of 10 m. As targets, white calico with dimensions of 100x150 cm was used, stretched on a wooden frame, or fixed on a chipboard. The distance between the target and the barrier was 100 cm, which roughly corresponded to the distance from the windshield of the car to the driver and the passenger in the front seat. The studies were carried out using the SEM "Hitachi FlexSem1000 II" and the energy-dispersive X-ray spectrometer "Bruker Quantax 80". Results. As a result of the conducted research with the help of microscopy, the presence of 7 types of foreign bodies on the surface of the target was established, which are the products of the destruction of the fire projectile and the barrier: glass fragments; glass fragments; crumbly deposition of glass particles; glass fragments caked with the metal of the projectile; fragments of the projectile; spherical metal particles; overlays of molten metal in the form of puddles. With the help of energy dispersion analysis, it was possible to determine the elemental composition of the particles of the barrier, the fire shell, and to identify the overlap of the target particles. Conclusion. As a result of the experimental study, it was found that the use of SEM and EDS analysis significantly increases the effectiveness and evidence-based expert research in solving the problems of causing damage through the barrier-the windscreen of modern cars. Key words: scanning electron microscopy, gunshot trauma, energy dispersion analysis, fragments of the barrier.


2005 ◽  
Vol 37 (3) ◽  
pp. 189-197 ◽  
Author(s):  
N. Djordjevic

The influence of Bi2O3 on the process of cordierite ceramics preparation, 2MgO-2Al2O3-5SiO2 (MAS) was investigated. The following binary systems were used for the presented research: MgO/Bi2O3 (sintered at 820?C and 1100?C), Al2O3/Bi2O3 and SiO2/Bi2O3 (sintered at 1100?C). The composition of these systems consisted of 80% of oxide and 20% Bi2O3. The effects of sintering, composition and morphology were investigated by X-ray diffraction, scanning electron microscopy and EDS analysis. It has been found that Bi2O3, besides a liquid phase, forms intermediary unstable compounds with MgO and Al2O3. MAS ceramics were sintered with 10% Bi2O3 at 1000?C, 1100?C and 1200?C. .


Author(s):  
Ann Chidester Van Orden ◽  
John L. Chidester ◽  
Anna C. Fraker ◽  
Pei Sung

The influence of small variations in the composition on the corrosion behavior of Co-Cr-Mo alloys has been studied using scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and electrochemical measurements. SEM and EDX data were correlated with data from in vitro corrosion measurements involving repassivation and also potentiostatic anodic polarization measurements. Specimens studied included the four alloys shown in Table 1. Corrosion tests were conducted in Hanks' physiological saline solution which has a pH of 7.4 and was held at a temperature of 37°C. Specimens were mechanically polished to a surface finish with 0.05 µm A1203, then exposed to the solution and anodically polarized at a rate of 0.006 v/min. All voltages were measured vs. the saturated calomel electrode (s.c.e.).. Specimens had breakdown potentials near 0.47V vs. s.c.e.


Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.


Author(s):  
William P. Wergin ◽  
P. F. Bell ◽  
Rufus L. Chaney

In dicotyledons, Fe3+ must be reduced to Fe2+ before uptake and transport of this essential macronutrient can occur. Ambler et al demonstrated that reduction along the root could be observed by the formation of a stain, Prussian blue (PB), Fe4 [Fe(CN)6]3 n H2O (where n = 14-16). This stain, which is an insoluble precipitate, forms at the reduction site when the nutrient solution contains Fe3+ and ferricyanide. In 1972, Chaney et al proposed a model which suggested that the Fe3+ reduction site occurred outside the cell membrane; however, no physical evidence to support the model was presented at that time. A more recent study using the PB stain indicates that rapid reduction of Fe3+ occurs in a region of the root containing young root hairs. Furthermore the most pronounced activity occurs in plants that are deficient in Fe. To more precisely localize the site of Fe3+ reduction, scanning electron microscopy (SEM), x-ray analysis, and transmission electron microscopy (TEM) were utilized to examine the distribution of the PB precipitate that was induced to form in roots.


Author(s):  
M. L. Zimny ◽  
A. C. Haller

During hibernation the ground squirrel is immobile, body temperature reduced and metabolism depressed. Hibernation has been shown to affect dental tissues varying degrees, although not much work has been done in this area. In limited studies, it has been shown that hibernation results in (1) mobilization of bone minerals; (2) deficient dentinogenesis and degeneration of alveolar bone; (3) presence of calculus and tears in the cementum; and (4) aggrevation of caries and pulpal and apical tooth abscesses. The purpose of this investigation was to study the effects of hibernation on dental tissues employing scanning electron microscopy (SEM) and related x-ray analyses.


Sign in / Sign up

Export Citation Format

Share Document